Avocado tree named &#39;BL516&#39;

ABSTRACT

‘BL516’ is a new and distinct variety of  Persea americana  tree. The variety exhibits an upright growth habit with strongly drooping branches; and forms pyriform, slightly obovate or occasionally rhomboidal shaped generally black-skinned fruit when ripe that lack shoulders and is well distributed around the tree. The fruit is comparable in size to that of the ‘Hass’ variety and matures slightly later then the fruit of the ‘Hass’ variety. ‘BL516’ fruit has yellow-green flesh of excellent eating quality that is free of obvious fibers. The ‘BL516’ variety forms leaves in greater quantity than the ‘Hass’ variety and displays moderate resistance to the  Persea  mite.

Genus and species: The avocado cultivar of this invention is botanically identified as Persea americana Mill.

Variety denomination:

The variety denomination is ‘BL516’.

BACKGROUND OF THE INVENTION

The invention relates to a new and distinct variety of avocado tree named ‘BL516’. The new avocado variety originated from a breeding program at the University of California, Riverside, for the development of new avocado varieties.

The seed that produced ‘BL516’ was collected in 1983 from open pollinated ‘Gwen’ (U.S. Plant Pat. No. 5,298) avocado plants. The exact pollen parent is unknown. Seeds were planted in a test planting area in Ventura County, California to produce avocado seedlings in the spring of 1985. A single plant of ‘BL516’ was selected with initial evaluation occurring in May 1991. ‘BL516’ was first top-worked by grafting onto Persea americana seedlings in the spring of 1991 in Irvine, California. The first fruit from the trees was tested in June 1994. This initial and subsequent asexual propagation confirmed that the new variety is stable and the progeny remain true to type.

BRIEF SUMMARY OF THE INVENTION

‘BL516’ exhibits the following combination of characteristics compared to other known varieties:

-   -   (a) ‘BL516’ has an upright growth habit with strongly-drooping         branches.     -   (b) ‘BL516’ has pyriform, slightly obovate or occasionally         rhomboidal-shaped, generally black-skinned fruit when ripe that         lacks shoulders and is well distributed around the tree. In         general, fruit is comparable in size and matures later than         fruit of the ‘Hass’ variety. The fruit has yellow-green flesh of         excellent eating quality that is free of obvious fibers.     -   (c) ‘BL516’ forms leaves in greater quantity than the ‘Hass’         variety.     -   (d) ‘BL516’ displays moderate resistance to the Persea mite.

BL516’ can be distinguished from all previously known avocado varieties including ‘Hass’ (U.S. Plant Pat. No. 35), ‘Gwen’ (U.S. Plant Pat. No. 5,298), ‘Sir Prize’ (U.S. Plant Pat. No. 9,709), ‘Lamb Hass’ (U.S. Plant Pat. No. 9,573), ‘N4(-)5’ (U.S. Plant Pat. No. 14,238), ‘3-29-5’ (U.S. Plant Pat. No. 14,239), and ‘BL 5-552’ (U.S. Plant Pat. No. 33,534) in view of its distinctive combination of characteristics.

‘BL516’ is believed to be well-suited for the production of quality avocados under commercial growing conditions.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

FIG. 1 illustrates typical unripe ‘BL516’ fruit (bottom row) compared to unripe ‘Hass’ fruit (top row). All fruit were harvested in Irvine, California in January 2022.

FIG. 2 illustrates four typical mature leaves of the ‘BL516’ variety. Leaves were collected from mature ‘BL516’ trees in the fall of 2014.

FIG. 3 illustrates a four-year-old top-worked tree of the ‘BL516’ variety growing in Irvine, California.

DETAILED BOTANICAL DESCRIPTION

The following is a description of ‘BL516’ trees that were grown at experimental orchards in Irvine, California unless otherwise indicated. The trees were approximately 2 to 17 years of age, and had been grafted on Persea americana seedling or clonal ‘Dusa’ rootstock. Where possible, comparison varieties were of approximately equivalent age. The comparative trees for the ‘Gwen’ variety, however, were mature and their exact age is unknown. Color information is designated with reference to the R.H.S. Colour Chart of The Royal Horticultural Society, London, England, 2001.

-   Tree:     -   -   Growth habit.—‘BL516’ is upright in growth habit with             strongly-drooping branches compared to an upright habit with             semi-drooping branches for the ‘Gwen’ and ‘Lamb Hass’             varieties; and upright and spreading habit with no drooping             branches for variety ‘N4(-)5’. Internode lengths on the             shoot are mostly short, but occasionally intermediate,             compared to mostly intermediate to short lengths for the             ‘Lamb Hass’ variety, intermediate lengths for the ‘Gwen’             variety, and intermediate to long lengths for the ‘N4(-)5’             variety.         -   Height.—Averaging 4.5 m for fully mature trees, about             10-15-years old, which is similar to the ‘N4(-)5’ variety,             compared to an average height of 4.4 m for the ‘Hass’             variety and 4.3 m for the ‘3-29-5’ and ‘Lamb Hass’             varieties.         -   Width.—Averaging 3.3 m for fully mature trees, which is             similar to the ‘3-29-5’ variety, compared to an average             width of 3.8 m for the ‘N4(-)5’ variety, 3.6 m for the ‘Lamb             Hass’ variety, and 4.1 m for the ‘Hass’ variety.         -   Canopy volume.—A comparison of ‘BL516’ canopy volume to             ‘Hass’ canopy volume is provided in Table 1. Volume was             determined using a formula that includes tree height and the             average canopy width taken at chest height from two trials,             one in Irvine, California and the other in Exeter,             California in the San Joaquin Valley. The trees were planted             in 2013 on ‘Dusa’ clonal rootstock. Measurements (Table 1)             were from mature trees, taken in Fall 2020. For the Irvine             site, ‘BL516’ tree volume was approximately 45% of the             canopy volume of Hass. The Exeter site provided similar             results, in which the ‘BL516’ tree volume was again about             45% of that of Hass.

TABLE 1 A comparison of ‘BL516’ to ‘Hass’ trees 7 years after planting in terms of average canopy width, tree height and canopy volume. Canopy Tree Canopy width Height Volume Site Variety (m) (m) (m³) Irvine BL516 3.46 b 4.23 a 27.19 b Hass 5.08 a 4.27 a 60.62 a Exeter BL516 2.77 b 3.09 b 13.63 b Hass 3.58 a 4.47 a 29.83 a Mean separation using Student-Newman-Keuls test at P ≤ 0.05. The designations “a” and “b” shown for each comparison characteristic at each site indicate that the means are statistically different at the 95% confidence level. Two “a” value designations for a given comparison indicate that the means are not statistically different at the 95% confidence level. Each site analyzed separately. Tree numbers for each site: Hass, 3 trees; BL516, 15 trees. Canopy width for individual trees was measured down the row and across the row and then averaged. Canopy volume calculated using the following formula: (Height* (Average canopy width)²)*0.5236

-   Main stem:     -   -   Bark.—Substantially identical to that of the ‘Hass’, ‘Gwen’,             ‘N4(-)5’, and ‘3-29-5’ varieties. The new wood is smooth             without corky lenticels. The old wood is corky in appearance             as observed with most other avocado varieties and light             brown or gray, RHS Greyed-Green Group 197D, in coloration.         -   Trunk size.—Trees average 49.1 cm in circumference, as             measured at approximately 30 cm above the soil line, above             the graft union and before major branching occurs, compared             to an average circumference of 47.2 cm for the ‘3-29-5’             variety, 57.8 cm for the ‘N4(-)5’ variety, 53.8 cm for the             ‘Hass’ variety, and 51.7 cm for the ‘Lamb Hass’ variety. -   Branch:     -   -   Color.—The color of a one-year-old branch is RHS Yellow             Green 145A. The most recent fully-formed young shoot (flush)             is also RHS Yellow Green 145A.         -   Smoothness.—The bark of a one-year-old branch is smooth.         -   Lenticels.—The lenticels of a one-year-old branch are             conspicuous and are RHS Yellow Green 143A in color, while             the lenticels of the most recent fully-formed flush are             generally RHS Yellow Green 144A. -   Young shoot (flush):     -   -   Intensity of anthocyanin coloration.—Strong, RHS Greyed             Purple Group N186C; Underside is RHS Greyed Orange Group             175A. Young leaf surface is medium glossy.         -   Young shoot color of lenticels.—Not very conspicuous. Yellow             to light green in color, generally RHS Yellow Green 144A.             Lenticels are generally between 0.8 mm and 2.9 mm in length             and are at a density of about 17 per c². Young shoot main             color is RHS Yellow Green Group N144A. -   Mature leaf:     -   -   Shape.—Generally lanceolate to somewhat oval with an acute             tip and an acute base. The shape is substantially the same             as that of ‘N4(-)5’ and ‘3-29-5’ varieties, compared to more             oval to somewhat lanceolate for the ‘Hass’ variety, or more             oblong lanceolate to lanceolate for the ‘Gwen’ variety. Leaf             base is acute and leaf apex is mostly acute, which is             substantially similar to ‘Gwen’ and ‘N4(-)5’ compared to the             ‘Hass’ or ‘3-29-5’ varieties, which have a more intermediate             to acute apex. The leaf blade of ‘BL516’ does not twist             along its entire length, nor does the apex of the leaf             exhibit twisting.         -   Bearing.—Alternate.         -   Attitude.—Outwards and upwards attitude of leaf to branch,             which is similar to the ‘Lamb Hass’ variety, compared to an             upwards attitude for the ‘N4(-)5’ variety, and an upwards             and outwards attitude for the ‘Gwen’ variety.         -   Length.—Approximately 18.2 cm compared to 19.9 cm for the             ‘Gwen’ and ‘Hass’ varieties, 15.3 cm for the ‘3-29-5’             variety, and 20.0 cm for the ‘N4(-)5’ variety.         -   Width.—Approximately 6. 9 cm compared to 6.7 cm for the             ‘Gwen’ variety, 7.8 cm for the ‘Hass’ and ‘N4(-)5’             varieties, and 6. 4 cm for the ‘3-29-5’ variety.         -   Leaf weight.—Approximately 2.78 grams compared to             approximately 3.95 grams for the ‘Hass’ variety, 2.05 grams             for the ‘3-29-5’ variety, 2.65 grams for the ‘N4(-)5’             variety, and 2.30 grams for the ‘Gwen’ variety.         -   Color.—Near RHS Yellow-Green Group 146A on the upper surface             and near RHS Yellow-Green Group 148D on the under surface.         -   Texture.—Pubescent when young and leathery when mature.         -   Venation.—Pinnate and near RHS Yellow-Green Group 145C in             color. Venation on upper surface is level with the rest of             leaf surface.         -   Margin.—Entire. Leaf undulation is very weak.         -   Petiole.—Generally 57.7 mm in length, and approximately 2.7             mm in diameter. Color of petiole is RHS Yellow-Green Group             153A or RHS Yellow Green Group N144A.         -   Anise aroma.—Absent. -   Flower:     -   -   Bud size.—Approximately 3.6 mm in length and 2.1 mm in             diameter.         -   Bud shape.—Ovate/oval initially, progressing to             oval/lanceolate.         -   Bud color.—RHS Yellow-Green Group 150C.         -   Opening.—Belongs to flowering group “B”. Opens as female in             the afternoon of the first day and closes in the evening or             early night to open as male the morning of the second day.             Accordingly, it can be inter-planted with complementary             flower types to possibly boost fruit set and yield by making             pollen available at the appropriate time. Pollinators (e.g.             European honey bees) can facilitate fruit set.         -   Petals.—Borne in two whorls of three perianth lobes. The             petals are intact, pubescent, and possess margins that are             not wavy or undulating. The petal coloration is near RHS             Yellow-Green Group 154C.         -   Stamen.—There commonly are nine fertile stamens with each             having four pollen chambers, two basal orange nectar glands,             and three staminoidia. The anthers are tetrathecal.         -   Pistil.—The single pistil has one carpel with one ovule. The             ovary is superior.         -   Pedicel.—Approximately 4.1 mm in length and 0.5 mm in             diameter. The coloration is near RHS Yellow-Green Group             151B.         -   Number of flowers on infloresence.—Approximately 10 flowers             per infloresence.         -   Fragrance.—Absent.         -   Bloom.—Bloom period in Irvine, California varies with             culture and environmental conditions. Based on observations             over several years, ‘BL516’ typically blooms from February             through May. -   Fruit and production characteristics: -   Fruit:     -   -   Length.—Approximately 10.0 cm.         -   Width.—Approximately 6.7 cm.         -   Weight.—Approximately 219.9 grams. This is comparable to the             ‘Hass’ variety, which averages 220.0 grams, but smaller than             the ‘3-29-5’ and ‘Lamb Hass’ varieties, which average 266.5             grams and 274.2 grams respectively for this comparison in             Irvine, California.         -   Shape.—Generally pyriform or slightly obovate to             occasionally rhomboidal with the fruit apex slightly             asymmetric in position with a slightly depressed to             flattened shape, and a diameter of 3.9 cm on average. The             fruit base is depressed to somewhat flattened with a             diameter of 5.8 cm on average. In comparison, the ‘Hass’             variety varies from ellipsoid to obovate, the ‘Gwen’ and             ‘N4(-)5’ varieties are generally an inverted high spheroid,             and the ‘3-29-5’ variety is generally inverted high             spheroid.         -   Color of skin.—Mature, hard fruit varies in a range             including RHS Green Group 136A, RHS Greyed-Green Group             N189A, RHS Green Group 135A, RHS Greyed Purple Group N186A             and RHS Greyed Purple Group 187A. Mature, soft fruit varies             in a range including RHS Greyed Purple Group N186A, RHS             Greyed Purple Group N186B, RHS Greyed Purple Group N187A,             and RHS Green Group 139A. Immature, hard fruit varies in a             range including RHS Yellow Green Group 144A, RHS Yellow             Green Group N144A, RHS Green Group 141B, RHS Green Group             143A, RHS Green Group N134A, RHS Green Group 141B, and RHS             Green Group 135B. Lenticels are distinct from background             color, much like the ‘3-29-5’ variety.         -   Texture of skin.—Slightly pebbled.         -   Presence of longitudinal ridges.—Absent.         -   Thickness of skin.—Somewhat leathery in consistency, not             corky or membranous. Skin thickness averages 1.2 mm compared             to 1.6 mm for the ‘Hass’ variety, 1.8 mm for the ‘3-29-5’             variety, and 1.5 mm for the ‘Lamb Hass’ variety.         -   Adherence of skin to flesh.—Minimal.         -   Main color of flesh.—RHS Yellow Group 11A or RHS Yellow             Group 13B towards the center of the fruit and RHS Yellow             Green Group N144B near the skin.         -   Width of intensely colored area next to the             skin.—Approximately 2.8 mm.         -   Conspicuousness of fibers in flesh.—Inconspicuous.         -   Fruit pedicel.—Approximately 10.9 mm in diameter. Pedicel             color is RHS Yellow Green 144A, RHS Yellow Green 145A or RHS             Yellow Green 146D and generally has a wrinkled surface.         -   Time of harvesting.—‘BL516’ typically ripens later than the             ‘Hass’ variety and is similar to the ‘3-29-5’ variety in             Southern California planting environments such as Irvine,             California. The typical optimal harvest period in Irvine,             California for good storability and eating-quality fruit is             approximately from April through July. -   Seed:     -   -   Length.—Approximately 4.1 cm.         -   Width.—Approximately 3.4 cm.         -   Weight.—Approximately 31.2 grams. This is smaller than the             ‘Hass’, ‘3-29-5’, and ‘Lamb Hass’ varieties measured, which             averaged 31.6 grams, 43.2 grams, and 35.1 grams             respectively.         -   Shape (in longitudinal section).—Almost equally tending             towards ellipsoid or broadly ovate compared to the ‘N4(-)5’             and ‘Gwen’ varieties, which are spheroid; the ‘Hass’             variety, which is variable but mostly ellipsoid; or the             ‘3-29-5’ variety, which is broadly obovate.         -   Shape (in cross section).—Generally circular.         -   Color of seed coat (fresh).—Ranges from RHS Greyed Orange             Group 166A, RHS Greyed Purple Group 183A, RHS Greyed Purple             Group 183B, RHS Greyed Orange Group 177A, RHS Greyed Purple             Group 186C, to RHS Greyed Purple Group 187A.         -   Cotyledon color.—Generally ranges from RHS Orange White             Group 159A and RHS Orange White Group 159B to Orange White             Group 159C. -   Productivity: Generally comparable to that of the ‘Hass’ variety,     but with perhaps less precocity. Table 2 provides a comparison of     cumulative fruit count, yield, average fruit size and alternate     bearing index. Fruit is borne on the inner branches of the tree,     however, and more protected from sun, wind or other weather damage.     ‘BL516’ has lower alternate bearing tendency than the ‘Hass’ or     ‘Lamb Hass’ varieties, similar to the ‘3-29-5’ variety.

TABLE 2 A comparison of ‘BL516’ to ‘Hass’ trees 9 years after planting in terms of cumulative fruit count, yield (kg), average fruit size and alternate bearing index. Cumulative Cumulative Average Alternate Fruit Weight fruit size Bearing Site Variety Count (kg) (g) Index Irvine BL516 610.5 a 131.2 a 213.5 a 0.59 a Hass 659.3 a 144.9 a 220.0 a 0.76 a Exeter BL516 210.1 a 29.7 a 165.4 a 0.33 b Hass 389.0 a 53.9 a 138.6 a 0.81 a Mean separation using Student-Newman-Keulstest at P ≤ 0.05. The designations “a” and “b” shown for each comparison characteristic at each site indicates whether the means are statistically different at a 95% confidence level. Two “a” value designations for a given comparison indicate that the means are not statistically different at a 95% confidence level. Each site analyzed separately. Trees planted in 2013 on ‘Dusa’ clonal rootstock. Tree numbers for each site: Hass, 3 trees; BL516, 15 trees. Alternate Bearing Index year-5 to year-10 were used to calculate I, based on the calculation of Hoblyn et al. (1936): I = (1/n) × [I^(n)/y − y//(y + y )], where yi is the observed yield in an ordered series of size n, and_yi − yi − 1_is the absolute difference between successive yields. Alternate bearing index calculated beginning with year 4.

-   Hardiness: Generally comparable to the ‘Hass’ variety (USDA     hardiness zone 9-11). For comparative purposes, the ‘3-29-5’ is     considered to be more cold-tolerant whereas the ‘Gwen’ and ‘N4(-)5’     varieties are considered to be less cold-hardy. -   Market use: ‘BL516’ avocados have excellent eating-quality and can     compete favorably with the ‘Hass’ variety for both fresh retail and     food service markets. The fruit exhibits post-harvest handling and     storage traits that allow it to be treated in much the same manner     as the ‘Hass’, ‘3-29-5’, and ‘Lamb Hass’ commercial varieties. The     narrow, upright canopy makes the ‘BL516’ variety a candidate for     high-density or hedge-row avocado plantings. Tree size and shape are     also desirable qualities for backyard growers. ‘BL516’ thus also has     retail nursery value. The B flowering-type indicates that it can be     a useful pollinizer for ‘Hass’, ‘Reed’, ‘3-29-5’, “Lamb Hass’, and     other flowering group A-type commercial varieties. 

1. A new and distinct variety of avocado tree named ‘BL516’ substantially as illustrated and described herein. 